Question: Reduce to lowest terms: $- \dfrac{7}{5} \div \dfrac{9}{4} = {?}$
Explanation: Dividing by a fraction is the same as multiplying by the reciprocal of the fraction. The reciprocal of $ \dfrac{9}{4}$ is $ \dfrac{4}{9}$ Therefore: $ - \dfrac{7}{5} \div \dfrac{9}{4} = - \dfrac{7}{5} \times \dfrac{4}{9} $ $ \phantom{- \dfrac{7}{5} \times \dfrac{4}{9}} = \dfrac{-7 \times 4}{5 \times 9} $ $ \phantom{- \dfrac{7}{5} \times \dfrac{4}{9}} = \dfrac{-28}{45} $